Peeling Paint - Advice needed.

[Mr.Nobody]

So I’m in the process of decorating the porch at the parents. I’ve noticed some paint peeling and I’m after some advice on the best way to fix it.

[Simpo Two]

It just looks very rough to me, needing a good sanding and some filling.

[Mr.Nobody]

The paint on top hasn’t adhered to what’s underneath. Would some 180G and some fine filler be okay along with Peel Stop??

[Condi]

Is it new paint which won't stick to what is there, or old paint which has peeled and you want to print over?

[Mr.Nobody]

Condi said:

Is it new paint which won't stick to what is there, or old paint which has peeled and you want to print over?

It’s new paint that hasn’t stuck to what’s underneath by the looks of it. Only in that spot though.

[reggie747]

Rising Damp.

[Mr.Nobody]

reggie747 said:

Rising Damp.

It’s an internal plasterboard wall. Plus the outside is k render and the damp course hasn’t been breached.

[Condi]

All you can do is wait for it to dry then sand it all back, removing what is underneath, fill it to the right level and repaint. If it's just that one area maybe something was different about the original paint, maybe it had been touched up with a different paint, something like that.

[OutInTheShed]

Looks like the paint has come away taking the surface with it.
I wouldn't rule out some damp being involved at some point.

It needs scraping back to see what it's like under paint.
If the surface isn't sound, seal it with whatever penetrating primer you choose.
I would use waterproof/external PVA, and get some filler on it, also with the same waterproof PVA mixed in, before it cures completely.

If you don't happen to have a pot of waterproof PVA on the shelf it's quite expensive, so use whatever.
Dilute water based primer or undercoat, or dilute exterior masonry paint perhaps.

You may need to sand the wall fairly smooth to end up with the same texture over the whole wall, or the repair will show.
It depends on what paint and roller you use.

The initial problem could have been the wall wasn't clean before painting, or some other cause.

[Mr.Nobody]

I’ll give it a light sand. Then clean with sugar soap. I’ve got some Peel Stop which is a fancy PVA I believe. Let that dry and see what it looks like.

[Condi]

It wants more than a light sand, you want to take it back to remove whatever is under the paint you've just put on. Ideally take it back to plasterboard, fill it, then a coat of primer and top coat to match the other work. If there are any marks in the plasterboard from damp or whatever then use a stain block primer.